The present invention relates to a lawnmower having a grass collection container which can be hung on the rear of the lawnmower frame and having a collected grass level indicating device with a level sensor which indicates how full the container is.
Such a lawnmower is known from U.S. Pat. No. 3,971,198. That lawnmower measures the fill condition in the grass container, rather than in the entry mouthpiece thereof In that lawnmower, the grass which has been cut is conveyed via a conveyor channel towards the cover of the container and the grass fills the container from the top. In the region of the cover, a bucket wheel is arranged inside the container. The wheel is turned by the same stream of air and the grass is entrained by the air stream. The rotation of the wheel is transmitted to an indicating disc on the outside of the cover. As soon as the container is full, this becomes evident from the fact that the indicating disc becomes stationary, which shows that the bucket wheel is clogged by grass and can no longer rotate.
Such a bucket wheel arrangement cannot be used when the grass is conveyed into the container from below, via a mouthpiece, and builds up in the container from the rear. In such lawnmowers, the collection container must be emptied upon occurrence of different degrees of filling, depending on the degree of wetness of the cut grass. This is to prevent the grass from being deposited on the ground instead of entering into the collection container, which would require gathering up the deposited grass.